What are the risks of radioactive tracers in bone scans? is there risk of nephrogenic systemic fibrosis, and should creatinine be checked before test?

No: NSF is a rare condition sometimes associated with gadolinium administration (contrast) during an MRI exam in patients with renal disease. This is not the same radioactive tracer used in bone scans, usually Technesium 99m. As a matter of fact, gadolinium is not radioactive. The amount of radioactive tracer used for a routine bone scan is so small, no significant side effects are expected